CS0-003 Incident Response and Management Practice Question
This CS0-003 practice question tests your understanding of incident response and management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
The following output is from a compromised server:
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 10.0.0.5:3389 192.168.1.10:54321 TIME_WAIT
tcp 0 0 10.0.0.5:54321 198.51.100.20:4444 ESTABLISHED
tcp 0 0 10.0.0.5:22 10.0.0.1:50001 ESTABLISHED
Refer to the exhibit. An analyst reviews the output from a netstat command on a server. Which connection is MOST likely indicative of command and control (C2) activity?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The following output is from a compromised server:
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 10.0.0.5:3389 192.168.1.10:54321 TIME_WAIT
tcp 0 0 10.0.0.5:54321 198.51.100.20:4444 ESTABLISHED
tcp 0 0 10.0.0.5:22 10.0.0.1:50001 ESTABLISHED
A
10.0.0.5:22 to 10.0.0.1:50001
Why wrong: SSH to internal IP is normal management traffic.
B
10.0.0.5:54321 to 198.51.100.20:4444
External IP on port 4444 from an ephemeral port is suspicious and common for C2.
C
All connections are normal.
Why wrong: The connection to 198.51.100.20:4444 is abnormal and likely C2.
D
10.0.0.5:3389 to 192.168.1.10:54321
Why wrong: RDP to internal IP is typical administrative traffic.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
10.0.0.5:54321 to 198.51.100.20:4444
Option B is correct because the connection from a high ephemeral port (54321) on the server to an external IP (198.51.100.20) on port 4444 is a classic indicator of C2 activity. Port 4444 is commonly associated with Metasploit's default reverse shell listener and other malware frameworks, while the use of a non-standard high source port and an external destination suggests outbound beaconing or command reception.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
External IP on port 4444 from an ephemeral port is suspicious and common for C2.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
All connections are normal.
Why it's wrong here
The connection to 198.51.100.20:4444 is abnormal and likely C2.
✗
10.0.0.5:3389 to 192.168.1.10:54321
Why it's wrong here
RDP to internal IP is typical administrative traffic.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the candidate's ability to recognize that not all high-port connections are malicious; the trap here is that options A and D use high ephemeral ports but are normal internal administrative traffic, leading candidates to incorrectly flag them as suspicious instead of focusing on the external destination and the specific C2-associated port 4444.
Detailed technical explanation
How to think about this question
C2 frameworks often use high-numbered ephemeral source ports to blend with legitimate traffic, but the destination port 4444 is a well-known signature for Metasploit's reverse_tcp payload. Netstat output showing an established connection to an external IP on a non-standard port should be cross-referenced with process information (e.g., using 'netstat -b' on Windows or 'lsof -i' on Linux) to identify the associated executable, as C2 traffic often originates from a process masquerading as a legitimate service.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CS0-003 question in full detail.
Incident Response and Management — This question tests Incident Response and Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 10.0.0.5:54321 to 198.51.100.20:4444 — Option B is correct because the connection from a high ephemeral port (54321) on the server to an external IP (198.51.100.20) on port 4444 is a classic indicator of C2 activity. Port 4444 is commonly associated with Metasploit's default reverse shell listener and other malware frameworks, while the use of a non-standard high source port and an external destination suggests outbound beaconing or command reception.
What should I do if I get this CS0-003 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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